(1) Field of the Invention
The invention is in the field of atmospheric fluidized bed combustion systems. More particularly, the invention relates to a solids recirculation system for the fluidized reinjection of carryover into a fluidized bed combustor.
(2) Description of the Prior Art
In one prior art fluidized bed combustor unit, carryover recirculation for the fluidized bed combustor is accomplished by using an air eductor system feeding a pneumatic transport line. The eductor type system operates on a venturi principle and transfers the carryover particles by drawing them from a cyclone collect hopper. Such a system is in use in the fluidized bed combustion system installed at Georgetown University in Washington, D.C.
The air eductors accomplish the dual function of building up the pressure to the combustor fluidized bed height level and providing the air for the pneumatic transport of the solid material. However, the air eductors require a very high energy jet, which upon dissipation results in high abrasion rates even for the special materials employed. Furthermore, the bulk type of flow for the solid material upstream of the air eductor and the configuration of the air eductor's axis with respect to the flow of the material make pluggage likely.